Correct size for reproducing representative technical viewpoint images.

Hi all, I'm having a bit of a nightmare producing some images for a Landscape Visual Impact Assessment. I need to show images which accurately represent the impact of a development. The usual methodology is to use a 50mm lens (on my cropped sensor I am using a 35mm lens giving a 52mm equivalent - a 38.2 degree angle of view).

I guess the simple question to ask is, what size does the image need to be displayed on the page to represent the view faithfully - at a viewing distance of 300mm? To further clarify, imagine the image was being printed on transparent paper and you held it in front of your face at a distance of 300mm in the spot the picture was taken - the image and the view seen through the paper should match.

Is there any way of calculating this?

Whew, thanks Barrie! Thanks for breaking the calculation down for me as well.

Now I know why I should have tried harder at maths all those years ago! Great stuff

We're using panoramas as well - unfortunately they're shot in portrait format and will be cropped top and bottom but I guess as long as the red square (indicating a landscape format shot of the same focal length) is reproduced at 207.15mm wide, the rest of the image will also be correct.

I'm not with why you would do the pano then crop to the same size as you could achieve with a single shot?

If you have shot in portrait format and use 207.18 as the height of the image you could make it as wide as the Pano or paper would allow.

It's just we have to get two panos to a page in Indesign, and as the panos were hand held there are bits at the top and bottom which need cropping anyway. But you're right, I can still use the long edge of a portrait format shot to do the same thing - thanks.

You don't need angle of view and tans. It's just similar triangles.

300/35 = 8.57 magnification factor so for 23.7 sensor it's
8.57 x 23.7 = 203.1mm

Alternative use 297mm A4 paper = 297/23.7 = 12.53x mag.

View at 12.53 x 35mm = 438.6mm

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There are firms that do this for a living using the digitised drawings to accurately paste into a street view or landscape. I would recommend getting a couple of quotes as otherwise you could be at risk of misrepresentation if you get it wrong - google 'architectural visualisation'.

I'm a landscape architect by the way! Barrie's advice tallies with the landscape institute guidance I've dug out so thanks again Barrie!

I'm not convinced that landscape and architectural practices do size their images in a representative way as a matter of routine, from what I see it's generally a case of making it fit in the page